Propellers have moved motorized water craft ever since they were invented but a simplified way of moving on the surface of the water would make electric craft quieter and more efficient.

A simple chain mechanism with paddles attached would get maximum propulsion when interacting with the water, with minimal energy used similar to how ducks swim.

Built sturdy enough, the paddles could take the craft onto shore or a landing device could be lowered to protect the paddles.

The illustration only show a jet-ski like contraption, but the low profile of the propulsion system could be build it into all sort of platforms including docks, barges or even larger craft.